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Title: Molecular photoelectron angular distribution rotations in multi-photon resonant ionization of H{sub 2}{sup +} by circularly polarized ultraviolet laser pulses

We study effects of pulse durations on molecular photoelectron angular distributions (MPADs) in ultrafast circular polarization ultraviolet resonant ionization processes. Simulations performed on aligned H{sub 2}{sup +} by numerically solving time dependent Schrödinger equations show rotations of MPADs with respect to the molecular symmetry axes. It is found that in multi-photon resonant ionization processes, rotation angles are sensitive to pulse durations, which we attribute to the coherent resonant excitation between the ground state and the intermediate excited electronic state induced by Rabi oscillations. Multi-photon nonresonant and single photon ionization processes are simulated and compared which exhibit a constant rotation angle. An asymmetry parameter is introduced to describe the pulse duration sensitivity by perturbation theory models. Influence of pulse frequency detunings on MPADs is also investigated where oscillations of rotations are absent at long pulse durations due to nonresonance excitation.
Authors:
; ;  [1]
  1. Laboratoire de Chimie Théorique, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1 (Canada)
Publication Date:
OSTI Identifier:
22415636
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 14; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ANGULAR DISTRIBUTION; ASYMMETRY; COMPARATIVE EVALUATIONS; EXCITATION; GROUND STATES; HYDROGEN IONS 2 PLUS; MULTI-PHOTON PROCESSES; OSCILLATIONS; PERTURBATION THEORY; PHOTOIONIZATION; POLARIZATION; SCHROEDINGER EQUATION; TIME DEPENDENCE; ULTRAVIOLET RADIATION